Mr. Frazier. Yes, they do.
Mr. Eisenberg. Commissioner Boggs, may I introduce these as 557?
Representative Boggs. They may be admitted.
(The items referred to were marked Commission Exhibit No. 557 for identification and received in evidence.)
Mr. Eisenberg. These were the only two cartridge cases fired as tests in Exhibit 139—as tests for the purpose of identification of the cartridge cases which you examined before, 543, 544, and 545?
Mr. Frazier. Yes, sir; these two were used in those tests. There were many other cartridge cases fired, but not for that purpose.
Mr. Eisenberg. Can you explain how you are able to come to a conclusion that a cartridge case was fired in a particular weapon to the exclusion of all other weapons?
Mr. Frazier. Yes, sir; during the manufacture of a weapon, there are certain things done to the mechanism of it, which are by machine or by filing, by grinding, which form the parts of the weapon into their final shape. These machining and grinding and filing operations will mark the metal with very fine scratches or turning marks and grinding marks in such a way that there will be developed on the surface of the metal a characteristic pattern. This pattern, because it is made by these accidental machine-type operations, will be characteristic of that particular weapon, and will not be reproduced on separate weapons. It may be a combination of marks that—the face of the bolt may be milled, then it may be in part filed to smooth off the corners, and then, as a final operation, it may be polished, or otherwise adjusted during the hand fitting operation, so that it does have its particular pattern of microscopic marks.
The bolt face of the 139 rifle I have photographed and enlarged in this photograph to show the types of marks I was referring to.
Mr. Eisenberg. You took this photograph yourself, and it is a photograph of the bolt face of the 139 rifle?